I'm having the following problems: - after latest El Capitan update, my Macbook Pro (mid 2010) crashes (turns off) during boot. - I'm unable to boot in safe mode, the only way is recovery mode. - I've run disk utility with ok results. - I've done PRAM reset with no effect. - I'm trying to reinstall El Capitan as a last resort but I'm getting the following error message: "An error occured while preparing the installation. Try running this application again." Currently I'm really stuck in the middle of nothing, everything I've tried goes terribly wrong and I have no clue what is going on. Please help, Thanks.